Gas-phase selective oxidation of alcohols: In situ electrolytic nano-silver/zeolite film/copper grid catalyst

The selective oxidation of a series of alcohols to their corresponding carbonyl products was carried out over a rationally designed in situ electrolytic nano-silver/zeolite film/copper grid (SZF) catalyst, which was prepared by a combination of the seed-film method for the fabrication of an ultrathin zeolite film and the in situ electrolytic process for the formation of highly dispersed silver nanoparticles. At a relatively low reaction temperature (ca. 320 degrees C), the SZF catalyst with highly dispersed in situ electrolytic silver nanoparticles exhibited much higher activity for the oxidation of mono-alcohols and higher selectivity for ketonic aldehyde in the oxidation of di-alcohols than the conventional bulk electrolytic silver catalyst. On the basis of the combination of diffuse reflectance ultraviolet visible spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and thermoanalysis, the remarkably high activity and selectivity of the SZF catalyst was attributed to the highly dispersed silver nanoparticles, which were stabilized by the zeolite film against sintering, and, accordingly, a large amount of Ag+ ions and Ag-n(delta+) clusters existed in the silver nanoparticles. The improvements of the catalytic performance of the SZF catalyst in a wide application extension will bring new concerns in both theoretical and applied fields. (c) 2005 Elsevier Inc. All rights reserved.